Preparation Of Two Functional Covalent Organic Framework Materials And Their Application In Food Safety Detection

In recent years,food safety has attracted more and more attention.With the increase of food types,food safety problems have emerged,which is directly related to the safety of people’s lives,economic development and social stability.Therefore,how to detect food contaminants quickly and sensitively becomes an urgent problem to be solved.The rapid development of nanomaterials provides a new opportunity for food safety detection technology.In particular,covalent organic framework（COFs）materials with large specific surface area,adjustable pore structure and high crystallinity show broad application prospects in the fields of food safety,biomedicine,electrochemical sensing detection and enrichment of adsorption materials.In this paper,Au NPs@COFs nanocomposites and magnetic Fe₃O₄@COFs nanocomposites were prepared by in-situ reduction method and layer assembly method respectively,and the two kinds of functional COFs materials were studied from the two aspects of sensor configuration and sample adsorption and detection respectively.A novel electrochemical sensing method for dopamine（DA）and an efficient removal and detection method for ethyl carbamate（EC）were established.The electrochemical sensor based on Au NPs@COFs composite nanomaterial showed excellent catalytic performance for DA,and the detection limit of DA sensor was 0.21μmol/L.The new method was applied to the rapid detection of DA in real samples（meat）.The new adsorbent combined with GC-MS/MS method based on Fe₃O₄@COFs composite material can detect EC in the range of 50-1600μg/L with the detection limit of 1.2μg/L.The new adsorbent showed high efficiency and rapid adsorption performance in the pretreatment of samples,and was used to remove EC from eight kinds of liquor with different flavor.This study provides a reference for the application of COFs in the detection of small molecules of food contaminants.